Straightening machine for metal bars



June 27, 1944. L. LOEWY ETAL STRAIGHTENING MACHINE FOR METAL BARS FiledMay 21, 1941 2 Sheets-Sheet 1 INVENTORS u/ow/e LoEwy. FRANK SIDNEY s TEEIW ATTORNEYS June 27, 1944,

L. LOEWY ETAL STRAIGHTENING MACHINE FORMETAL BARS 2 Sheets-Sheet 2IIIIIIIII'IIIIIIIIIA INVENTORS- wow/6 405w) Filed May 2 1, 1941 FRANKS/DNEY 564 E2 ATTORNEYS Patentedlnne 27, 1944- 2,352,442 srns'rcn'rnnmdmom FOR METAL sans Ludwig Loewy, Bournemouth, and Frank Sidney Salter,Parkstone, -England,,assignors, to The Loewy Engineering Company,Limited, London, England, a'corporation of Great Britain ApplicationMay. 21, 1941, Serial No. 394,538

In Great Britain May 23, 1940 8 Claims. (Cl. its-2i This inventionrelates to a straightening machine for metal bars and, in particular,profiled 'or flanged bars of non-ferrous metals, such as j aluminium,magnesium and their alloys, which are manufactured in extrusionpresses.I Recent developments in this field of extrusio between the .two'gripping heads, this carriage having a die with anaperture correspondingto the correct shape or the sections of the bar under treatment, andbeing'further adapted to be trav- I have made it possible to produce.large bars of intricate sectional contour and of large size. The barsleave the extrusion presses while still hot,

and it frequently occurs that they become dejormed through unevencooling or for other reasons, and are buckled or twisted either locallyor throughout their entire length.

It has, therefore, become necessary tosubiect the bars to straighteningand untwisting operations, with a view to bringing them into correct'rectilineal conditio The machines used hitherto for thispurposecomprise a 'bed or frame on which two gripping heads are mounted,each containing a set 'of holders for jaws are adapted to clamp the bar.

Means are provided, preferablyin the nature of a hydraulic power driveassociated with one of the ri ping heads, to move the latter away,

' from the other with a bar placed in position. The bar can thusbesubjected to a tension beyond the yielding point of its material, withthe result that it is stretched out and all buckles and kinks'arememoved from it. One of the gripping heads is further adapted to bedisplaced along the frame" bed, so'as to allow the distance between thegripping heads to be adjusted. according to the dinerent lengths ofbars, means being -further provided for clamping the moveable grippinghead to the frame during the stretching operation, so. that ersedlongitudinally along the said bar. The object of this arrangement wastocorrect the relative angular position of any flanges and webs of thebar. This apparatus did 'not, however, permit the removal of localtwists from the bar between its ends,

The object of the present invention is to provide a strazighteningmachine for metal bars which allows the removal of local twists in amanner which is simple, efllcient and thorough at the same time. Thisobject is attained by providing an unrestricted passage for the barsthrough which they can be moved through the it can take up the reactionof the tensional force applied'tothe bar.

It has been proposed in a machine of the kind described above to makeone of thefg'rippingheads rotatable by means of aseparate power drivewhile a bar is clamped by the jaws of this head. By turning one headwith a bar clamped or to the gripping mechanism.

machine in" the direction of its axis, so that a bar can 'be made totake up any desired position with regard to the untwisting apparatus.provided in the machine. Thus, this apparatus can be brought intooperation on any part of the bar, e

so that local twists which occur between the ends of the bar can beeasily and speedily corrected.

This invention also provides for subjecting the bar to torsion at thesame time as a longitudinal pull is applied, so that both operations maywork together inlremoving deformations from the bar.

The passage through which the bars be moved is obtained by making allparts of the machine which are arranged in its axis hollow, whether theybelong to the hydraulic power drive In a preferred embodiment of themachine according to the invention, the ram of the .hy-

draulic power drive 'is hollow and an annular pressure chamberformedaround the ram, the

- ram having ashoulder which acts as a piston in therein, twists couldbe removed, but only if they occurred at that end of thebar which wasclamped to the head provided withthe turning means. It was, however,impossible to eliminate the twists which occurred between the ends ofthe bar. Further, it has not been powble in this known machine to twistthe atthe same time as the stretching power is applied, because nothrust hearing was provided for therotatlng head which was-capable ofsustaining the required machine for bars has.

the pressure chamber when the ram is being axially-moved.

Means are arranged on both sides of the, hy-- -draulic main drive forreturning the gripping head attached to the ram to its startingposition. The hollow ram is also capable of rotating within the pressurechamber and, during this torsional movement, the'pressure fluid supportsthestretching load, in the manner exemplified by afluid-supported thrustbearing as commonly em-' r ployed in other. machinery.

-I or purposes of untwisting, the slippinghead attached to the hollowram is rotatably mounted on a carrier and associated with anindependent.

drive by means of which the gripping head can bebeenproposedwhereinacarriagewasprovidedttturnodwhilothebarisclampedtherein.

Bars are charged into the machine according to the invention by passingthem through the hollow ram and gripping heads so that that part of thetwisted part after another to the action of the untwisting apparatus.

The machine according to the invention hagthe further advantage that thestretching operation need not necessarily be applied over the wholelength of the bar as was the case with the former type of machine, butthat it can be applied selectiveiy to individual parts of the bar adepending tongue 29 which engages guideplates 30 on frame "I from below,so that the .carrier I6 is locked against rotarymovement.

with a consequent increase in efficiency and a" saving of power. i

A further advantage is that the bars may be passed into the machine atone end, straightened, and discharged at the other end, thus alwaysfollowing one another inthe same longitudinal direction, givingconvenience in handling.

In order to mak the invention more clearly understood, one embodimentwill be described by way of an example with reference to theaccompanying drawings in which: I

Fig; 1 is a sectional elevation for a straightening machine according tothe invention, partly in section.

Fig. 2 is a sectional plan view of the machine.

Figs. 3 and 4 are both sectional views of the same, looking towardsopposite ends.

Arranged upon frame I! are the two gripping heads II and I2 of themachine, each head being equipped with a set of jaw-holders IS. The lawholders are adapted to serve as sockets for in- .terchangeable jaws (notshown in the drawings) which are shaped in accordance with the contourof the bar under treatment, and are slidably supported on inclinedsurfaces of the gripping heads by means of hydraulic rams M.

The inclination .of the supporting surfaces is such that by moving ramsIt, the Jaw-holders 13 approach each other, whereby a bar 3 is clampedfast between the jaws. As soon as the rams ll are relieved of pressurefluid, they return, with the jaw-holders it, into the inopera- 'tivepositionv under the action of pull-back :sprinEs Ii.

Gripping head H is supported on frame I I by means of a carrier l6 andis attached to an ex-- tension ll of a hollow ram It. This ram, to-

gether with a cylinder ltjforms the main hydraulic drive of thestraightening machine by which tension'is applied to the bar B beyond Itwill, however, be apparent that ram extension l1 and also ram ll ;willpartake in the rotary movement of gripping head II. The stretching loadexerted on the ram will then be supported by the pressure fluid inchamber 20 so that any other bearing for taking up the axial thrust canbe dispensed with, the only friction which the ram and the ram extensionhave to overcome on their rotation being that at the packings.

Gripping head I! is supported directly on the guide-plates 30 'of frameIn by means of two sets of rollers ll, one set of which is driven bymeans of an electric motor 32 through the intermediary of a worm gear33. In this way, the gripping head I: can be moved along frame It andcan take up any desired position along the guideways 30. Tongues 34 areprovided at the base of gripping head I! which engage the guideways 30from below and serve to lock the gripping head against any rotarymovement, in

' the same way as the tongue 2! acts with regard to carrier I (Fig. 4)

Means are provided for anchoring gripping head I! along the frame ll,these, means comprising a series of teeth I! provided at both sides ofthe frame, and a pair of levers I8 pivoted at 31' to gripping head l2and provided with lugs 38 which can be dropped into'the gaps between theteeth 35. In order to release the gripping head It, fluid-operatedcylinders 39 are arranged on levers 36 which co-operate with rams 40mounted on independent rollers 4|.

Throughout the drawings, the inlet and outlet piping for thefluid-operated rams ll, II and 40 are only diagrammatically indicated,and

. their control valves are omitted altogether since inder. Arranged atboth, sides of cylinder I! are return cylinders 22 with fluid-operatedrams 23 which are. associated ,with the carrier 16 for shifting thegripping head back intoits initial position. I

the-fluid pressure system does not form part of the present invention.It is, however, to be understood that an annular distribution chamber 42is provided with the carrier I for the purpose the rear wall of grippinghead I! has a central aperture 43. The area of these passages, as wellas that of the bore in parts I! and I0, is sumciently large 'toaccommodate bars of any cross section which the machine is capable ofhandling. By these means it is possible to move the bars freely from oneend of the machine to the other, passing them through the main hydraulicdrive as well as through both gripping heads. This permits thebars to becharged at one end of the machine and to be removed at the other end:and allows the bars to go through this machine .in one continuous flowand always in the same direction. This facilitates the operation of gthe machine, shortens the time necessary for said plunger to actuate thesame to move the chucks apart for drawing a bar mounted in and extendingaxially through said chucks and means for rotating the first mentionedchuck to twist the bar.

3. In a machine for straightening bars of the type described, a frame,two gripping heads mounted on said frame, each gripping head having anopening therethrough in axial alignment with the opening in the othergripping head other gripping head and, further, that the distancebetween the two gripping heads is freely adjustable. This enables .thepoint of engagement of the bar .with the gripping heads to be selectedat will and gives the two further advantages that (a) any part of thebar can be submitted to the direct action of the untwisting apparatusembodied in gripping head H and (b) the straightening effort can beselectively applied to individual parts of the bar only, and need not beapplied all over its length. Twists can. therefore, be removed from thebarwherever they occur, whether. at the ends of the bar or atintermediate parts, and, by applying the straightening effort to a partof the bar only, a

saving in power and an increase in efficiency is achieved. i v

Finally, the machine according to the invention allows the rotary powerto be applied at the .stock, a chuck carried by said plunger havingbar-gripping jaws, said jaws forming an openingin linewith the hollowplunger and movable inwardly to grip a bar extending through saidthrough which'bars may be passed from end to end of the machine, meansin gripping heads is to anchor said gripping head on said frame atspaced distances fromv the other gripping head, and power meansconcentric with the opening through the other gripping head directlyattached thereto and having an opening therethrough,

.20 through which bars may pass, to move said gripping headlongitudinally relative to the anchored gripping head, and means torotate one of said gripping heads while the gripping heads are beingmoved longitudinally relative to each other.

4. In amachine for straightening bars of the type described, a frame,two gripping heads movably mounted on said frame, each gripping headhaving an opening therethrough in axial alignment with the opening inthe other gripping head through which bars may be passed from end tosame time as the straightening power, which was Y end of the machinemeans in said gripping heads to grip bars at spaced points along thebars, means to anchor one of said gripping heads on said frame at spaceddistances from the other gripping head, power means concentric with the10 head, said power means being rotatable, and pow er means to rotateone of said plunger, a tailstock mounted on said bed and movable towardand from the headstock, a second chuck carried by said tailstock andhaving bar-gripping jaws movable inward to grip the bar.

bar to pass longitudinally therethrough.

2. In apparatus for straightening bars, in combination, a bed, a'headstock having an axial opening for passage of a bar, mounted on saidbed, a hollow stepped plunger movable axially and rotatably in saidheadstock, a chuck having an axial opening .in alignment with saidhollow plunger and carried by said plunger and having bar-gripping jawsmovable diagonally inward to opening through the other gripping head andhaving an opening therethrough, through which bars may pass, to movesaid gripping head longitudinally relative to the anchored grippinggripping heads relative to the other gripping head. 9

5. In a machine for straightening bars of the type described, a frame,two gripping heads movably mounted on said frame, each ripping headhaving an opening therethrough in axial alignto grip bars at spacedpoints alongthe bars,

'being open centrally therethrough to permit a,

means to anchor one of said gripping heads on said fram at spaceddistances from the other gripping head, hollow power means concentricwith the opening through the other gripping head to move said grippinghead longitudinally relasaid frame, each gripping head having anopengrip a bar extending through said plunger, a

carriage-having an opening in axial alignment with said hollow plungerfor passage of a-bar mounted on said bed and adjustable toward'and .fromsaid headstock, meansto anchor the carriage on said bed, a, second chuckhaving an axial opening for passage of a bar carried by said carriageand having means to grip a bar, and means for applying fluid pressurebehind the step of 7 frame at spaceddistances from the other grip pinghead,po'wer means concentric with the opening therethrough in axialalignment, with the opening in the other gripping head through 4whichbars maybe passed from end to end, of the machine, means in saidgripping heads to grip bars at 'spaced points along the bars, means toanchoione of said gripping heads onsaid ing through the other grippinghead to move stituting a stepped hollow piston surrounding the openingthrough said gripping head and a cylinder surrounding said pistonwhereby fluid pressure may be applied uniformly around said piston tomove said gripping head away from the anchored gripping head, and meansto rotate one of said gripping heads relative to the other grippinghead.

7. In a machine for straightening bars of the type described, a frame,two gripping heads movably mounted on said frame and extending abovesaid frame, each gripping head having an opening therethrough in axialalignment with the opening in the other gripping head through which barsmay be passed from end to end of the machine, means in said grippingheads togrip bars at spaced points along the bars, means to anchor oneof said gripping heads on said frame at spaced distances from the othergripping head, power means concentric with the opening through the othergripping head to move said gripping head longitudinally relative to theanchored gripping head, said power means constituting a gripping headaway from the anchored gripping head, and means to rotat said pistonsimultaneous with the application of fluid pressure thereto. 8. In amachine for straightening bars of the type described, a frame, twogripping heads movably mounted on said frame, each gripping head havingan opening therethrough in axial alignment with the opening in the othergripping head through which bars may be passed from end to end of themachine, means in said grip ping heads to grip bars at spaced pointsalong the bars, means to anchor one of said gripping heads on said frameat spaced distances from the other gripping head, power means concentricwith the opening throughthe other gripping head to move said grippinghead longitudinally relative to the anchored gripping head, said powermeans constituting a stepped piston surrounding the opening through saidgripping head and a cylinder surrounding said piston whereby fluidpressure may be applied uniformly around said piston to move saidgripping head away from the anchored gripping head, and means to rotatesaid.

piston simultaneous with th application of fluid pressure thereto, thegripping means in said power actuated gripping head being controlled bya plurality of fluid pressure actuated grip control cylinders andpistons, fluid passages through said stepped piston leading to each ofsaid grip control cylinders and a fluid chamber surrounding said pistonand communicating with said passages at all times regardless of thelongitudinal or rotational movement of said piston.

- LUDWIG LOEWY.

F. S. SAL'IER.

